text: Bioceramics are meant to be used in extracorporeal circulation systems (dialysis for example) or engineered bioreactors; however, they're most common as implants. Ceramics show numerous applications as biomaterials due to their physico-chemical properties. They have the advantage of being inert in the human body, and their hardness and resistance to abrasion makes them useful for bones and teeth replacement. Some ceramics also have excellent resistance to friction, making them useful as replacement materials for malfunctioning joints. Properties such as appearance and electrical insulation are also a concern for specific biomedical applications.
  Some bioceramics incorporate alumina (AlO) as their lifespan is longer than that of the patient's. The material can be used in middle ear ossicles, ocular prostheses, electrical insulation for pacemakers, catheter orifices and in numerous prototypes of implantable systems such as cardiac pumps.
  Aluminosilicates are commonly used in dental prostheses, pure or in ceramic-polymer composites. The ceramic-polymer composites are a potential way to filling of cavities replacing amalgams suspected to have toxic effects. The aluminosilicates also have a glassy structure. Contrary to artificial teeth in resin, the colour of tooth ceramic remains stable Zirconia doped with yttrium oxide has been proposed as a substitute for alumina for osteoarticular prostheses. The main advantages are a greater failure strength, and a good resistance to fatigue.
  Vitreous carbon is also used as it is light, resistant to wear, and compatible with blood. It is mostly used in cardiac valve replacement. Diamond can be used for the same application, but in coating form.
  Calcium phosphate-based ceramics constitute, at present, the preferred bone substitute material in orthopaedic and maxillofacial applications, as they are similar to the main mineral phase of bone in structure and chemical composition. Such synthetic bone substitute or scaffold materials are typically porous, which provides an increased surface area that encourages osseointegration, involving cell colonisation and revascularisation. However, such porous materials generally exhibit lower mechanical strength compared to bone, making highly porous implants very delicate. Since the elastic modulus values of ceramic materials are generally higher than that of the surrounding bone tissue, the implant can cause mechanical stresses at the bone interface. Calcium phosphates usually found in bioceramics include hydroxyapatite (HAP) Ca(PO)(OH); tricalcium phosphate β (β TCP): Ca (PO); and mixtures of HAP and β TCP.
  Table 1: Bioceramics Applications
  Table 2: Mechanical Properties of Ceramic Biomaterials